1. Field of Invention
This invention relates generally to grading or leveling apparatus that is attached to the front end of a tractor, and pertains more particularly to apparatus of this character that will additionally perform a sifting operation during the leveling procedure and which will also permit the transporting of the soil so as to more effectively and efficiently complete a leveling operation.
2. Description of the Prior Art
As pointed out in U.S. Pat. No. 3,556,228 issued on Jan. 19, 1971 to Orlan H. Mork for "APPARATUS FOR LEVELING SOIL AND THE LIKE," weighted boards had been dragged behind tractors in leveling soil, the patentee explaining that such devices were unsatisfactory, attributable to at least some degree to the tendency of the soil to pile up in front of the board and also escape around the outer edges thereof with the consequence that ridges were formed in the surface of the leveled soil. Also, as believed obvious, this type of device is unable to sort out unwanted debris.
To overcome such shortcomings the patentee in the above instance describes a frame comprised of several spaced cross-beams, each performing a scraping function. By tilting the apparatus, the soil, according to the patentee, is prevented from escaping around the edges or over the top of the apparatus.
Improvements over the earlier arrangement are embodied in U.S. Pat. Nos. 4,418,759 issued on Dec. 6, 1983to the same patentee for "SOIL LEVELING APPARATUS" and in a further improvement set forth in U.S. Pat. No. 4,448,258granted on May 15, 1984 to the same patentee for "SOIL LEVELING APPARATUS." Basically the improved apparatus eliminates undesirable ridge formations and a lessening of soil build-up along the interior sides of the apparatus because of the open interior design. In each of the patents, the apparatus makes use of transverse or cross-beams with a spacing therebetween providing the open interior design which makes it impossible to achieve any sifting action. Also, since the spacing forming the open interior between the transverse beams is quite appreciable, it follows that soil cannot build-up on the top of the apparatus so that it can be transported from one location to another.